From https://gstreamer.freedesktop.org/src/gst-libav/gst-libav-1.12.3.tar.xz.sha256sum
sha256 015ef8cab6f7fb87c8fb42642486423eff3b6e6a6bccdcd6a189f436a3619650 gst-libav-1.12.3.tar.xz
